The probe of the Admittance Switch forms one plate of a capacitance circuit, with the vessel wall making the second plate. The dielectric constant of the product between the probe and the vessel wall will cause a change of capacitance as the level approaches the probe. The change is detected, amplified and used to switch a relay for indication or control purposes. A special circuit is used to ignore product build-up between the sensing probe (active element) and guard, and also between the guard and vessel wall.
Thermal dispersion switches of gas and liquid flow, liquid level and interfacedetails
Compact, loop-powered ultrasonic level transmitters for continuous measurement of liquidsdetails
Capacitive level sensors that can measure liquids of all kind, foams, bulk goods, granulates, even in liquids that are sticky, pasty and regardless of their viscositydetails
Guided wave radar for level measurement of solids and liquids.details